Abstract
Eight Radopholus similis populations from three continents and different hosts were compared morphologically and morphometrically. Reflection of the posterior or anterior ovary or testis was common in all the populations. Variability of most taxonomic characters was frequent. Many of the individuals from the Indonesian population had a forked tail end. Scanning microscopy showed that males and females from different populations had several morphological differences, especially in the number of anterior hypoptygmata in the males and annules terminating the vulva of the females. Results of this study confirm that R. citrophilus is a synonym of R. similis.